Guiding catheters are commonly used during coronary angioplasty procedures to aid in delivering a balloon catheter or other interventional medical device to a treatment site in a coronary vessel. In a routine coronary angioplasty procedure, a guiding catheter is introduced into a peripheral artery and advanced over a guidewire through the aorta until the distal end of the guiding catheter is engaged with the appropriate coronary ostium. Next a balloon dilatation catheter is introduced over the guidewire and through the guiding catheter. The guidewire is advanced past the distal end of the guiding catheter within the lumen of the diseased vessel and manipulated across the region of the stenosis. The balloon dilatation catheter is then advanced past the distal end of the guiding catheter over the guidewire until the balloon is positioned across the stenotic lesion. After the balloon is inflated to dilate the blood vessel in the region of the stenotic lesion, the guidewire, balloon dilatation catheter and guiding catheter are withdrawn.
Guiding catheters typically have preformed bends formed along their distal portion to facilitate placement of the distal end of the guiding catheter into the ostium of a particular coronary artery of a patient. In order to function efficiently, guiding catheters should have a relatively stiff main body portion and soft distal tip. This stiffness has been provided in the past by using a reinforced construction or by using certain relatively stiff polymeric materials. The stiff main body portion gives the guiding catheter sufficient "pushability" and "torqueability" to allow the guiding catheter to be inserted percutaneously into a peripheral artery, moved and rotated in the vasculature to position the distal end of the catheter at the desired site adjacent to a particular coronary artery. However, the distal portion should have sufficient flexibility so that it can track over a guidewire and be maneuvered through a tortuous path to the treatment site. In addition, a soft distal tip at the very distal end of the catheter should be used to minimize the risk of causing trauma to a blood vessel or even puncturing the vessel wall while the guiding catheter is being moved through the vasculature to the proper position. Such a soft tip is described in U.S. Pat. No. 4,531,943. In addition, the inner surface of the guiding catheter should be lubricous to facilitate movement of guidewires, balloon catheters and other interventional medical devices therethrough.
Guiding catheters currently on the market attempt to achieve these goals with varying degrees of success. However, none of the previous or current designs have heretofore provided an optimum combination of features that yield a catheter with a stiff main body portion, a flexible distal portion and a soft distal tip that can be successfully used in coronary angioplasty procedures.
Therefore it would be desirable to provide a guiding catheter that has sufficient rigidity along its proximal portion for enhanced pushability and torqueability, yet has a flexible distal portion and soft tip to provide enhanced trackability and minimize trauma to the vessel wall.
It would also be desirable to provide a guiding catheter that has a lubricous inner surface to facilitate movement of guidewires, balloon catheters and other interventional devices therethrough.
It would be further desirable to provide a guiding catheter that is easy to manufacture.